And after that the Levites went in to do their service in the tent of meeting …: For to do their service, see verse 11 and 7.5; for the tent of meeting, see 1.1.

In attendance upon Aaron and his sons (literally “before Aaron and before his sons”) may be rendered “under [the supervision of] Aaron and his sons.” Compare verse 13.

As the LORD had commanded Moses concerning the Levites, so they did to them: See the comments on verse 20. The pronouns they and them refer to the Israelites and the Levites respectively.

Good News Translation changes the order of the two sentences in this verse, putting “the Levites were qualified to work in the Tent under Aaron and his sons” at the end, outside the scope of the implementation of the LORD’s instructions to Moses. Good News Translation‘s model may seem more logical but it obscures the fact that this section treats the Levites’ service in the Tent of Meeting as part of the instructions to Moses (see verses 13 and 19). This model also separates the means, namely, the purification of the Levites (verse 21), from the result, which is the Levites’ qualification to serve in the Tent (verse 22a). It also obscures the inclusio based on the key verbs “command” and “do” that enclose this paragraph (verses 20-22).

Quoted with permission from de Regt, Lénart J. and Wendland, Ernst R. A Handbook on Numbers. (UBS Helps for Translators). Miami: UBS, 2016. For this and other handbooks for translators see here .